Belt-drive for sewing-machine motors



H. MAIMIN. BELT DRIVE FOR SEWING MACHINE MOTORS.

APPLICATION FILED DEC-22' 1 919.

Patented May 3, 1921.

2 SHEETS-SHEET 1.

. H. MAIM'IN.

BELT DRIVE FOR SEWING MACHENE MOTORS.

APPLICATION men nc.22 m9.

Patented May 3, 1921.

2 SHEETS-SHEET 2.

3 vwe n toz UNITED STATES. PATENT OFFICE, t

mm mamm, or NEW YORK, N. Y.

BELT-DRIVE FOR SEWING-MACHINE MOTORS.

To all whom may concern: v

Be it known that I, HYMAN MAIMIN, a

Y citizen of the United States, residing at New 7 York city, in the county of New York, State of New York, have invented certain new and useful Improvements in Belt-Drives for Sewing-Machine Motors; and I do hereby declare the following to be a full, clear, and exact description of the invention, such as will enable others skilled in the art to which it appertains to make and use the same. 7

This invention relates to belt drives for sewing machine motors. I

Small electric motors are now generally used fordriving sewing machines, especially in the case of machines that are to beused continuously, as in the garment ndustry. It is customary to provide the motors with rheostats to prevent a sudden rush-of current when the motors are started under load and also to permit the speed of the machines 'to be controlled while they are m operation. The disadvantages of rheostats, particularly their cost and liability to get out of order, have led to the production of many arrangements 'for avoiding their use by running the motors continuously and bringing them into operative relation. to the. .machines whenever it'is desired that the latter be driven. In some of these prior arrangements the motors are fixed upon the tables of the sewing machines-and connected to frictional wheels which are adapted to be swung into engagement with the vhand.

wheels of the machines whenever it is desired'tooperate the latter. These arrangements, .however, require the use of extra members and in some cases, owing to the movement of the swinging members upon which the friction wheels are carried,- there is a change in-the tension of the driving belt.

I In power drives for sewing machines, par-. ticularly in the'garment ndustry,the mechanism should be arranged so I that; the machines maybe normally operated at a predetermined speed to' which-the operator is required to conform in the performance of his part of the work. In many of the prior. arrangements which have been proposed for eliminating the use of rheostats, the speed of the machines is directly cunder'the control of the operatorsand depends upon the effort expended by them in holding the-motors in operative-relation to the machines. :In the case of a. slow operator'it will be compara- W Specification of Letters Patent. Patented )Iay 1921. Application filed December 22, 1919. Serial No. 346,704. l

ativelyeasy for him to prevent his machine from being driven at the required speed, with the result that his production will be cut down, and the motor will not be operated at its'full load. 7 M

It has been proposed to overcome the disadvantagesmentioned above by pivoting the motor adJacent the hand wheel or driving 5 ject-to variations in the effort expended by" the operator as are prior arrangements ofthis I general charactrz. The arrangement does,

however,'permit "the operator to change thei speed of the machine from time to time assitatesa special act on his part which will not naturally *be performed under normalj maybe required,;-'but 'this alteration necesconditions '0 operation. In one embodiment of the invention described above, power may" be transmittedfrom the motor to the ma chine, by a-pulley on the shaft of the motor which is connected by a belt to a driving pulley on the shaft of-the machine, the mo tor beingiarranged to fall away from the machine to apply tension to the driving 4 belt. The position of the motor is controlled by atreadle in order that the hands of the operator may be free for manipulating his Work. The treadl'e which is normally ac-v tuated by a spring to swing the motor in such a manner as to slacken the drivmg belt has a flexible or lost motion connection to the motor so that when the effect of'the spring. is overcome by pressure upon the treadle, the flexible connection will become slack to permit the motor to fall awayfrom the machine and hold the driving belt under tension by the weight of the motor mile-j pendently. of the effect of the actuating spring. The arrangement does, however, permitthe speed of the machine to be controlled,- for, if the trea-dle is not pressed.

downwardly to its full extent, the flexible;

5 connection will remain-taut and balance the e motor so that the effect of its weight in. f producing belttension will be partly over come, and due to theslip between the belt and the pulleys there will be a resulting as I crease in the'speed of the machine.

by the belt may be maintained under sub-.

stantially constant tension, due to the weight of the motor and may be shifted from a: loose to a fast pulley on the motor shaft to start the machine, or in a reverse direction to stop the machine. The shifting mechanism is preferably under the control of a.

foot of t e-operator so that both hands are free for manipulation of his work. The normal condition of the'apparatus is such that the belt is held upon the loose pulley by the force of the spring acting upon a treadle,

but when the s rlng is overcome by pressure,

upon the tread e, the device operates to shift the belt to the fast pulley with Wl'llCll it 1s held in contact under conditions of substantially constant tension.

Theinvention thus provides an arrangement in which the motor may be driven continuously and conveniently and quickly brought into operative relation to the machine or removed therefrom as may be desired. When in operative relation the motor will drive the machine at the predetermined speed required for most eflicient operation, and this speed cannot readily be altered by the operator.

In some cases, however, it may be necessary to permit the operator to exercise control over the speed of the machine, and for this purpose the motor may be mounted so that it may be tilted about its pivot oint after the belt has been shifted to permit the speed of the machine to be varied in the same manner that it is controlled in the arrangement of my copending application mentioned above. For the sake of simplicity the apparatus is so constructed that there is a single operating connection between'the treadle and the motor, and the belt shifting mechanism is controlled by the initial movement of the motor as it falls away from the machine to cause'the belt to be shifted to the fast pulley. After the belt has been shifted the motor may swing through a further arc to tighten the belt. The treadle is actuated by aspring to restore the parts totheir normal condition, and as in the case of the arrangement of my copending application mentioned above, there may be a flexible or lost motion connection between the treadle and the motor so that the normal movement imparted to the treadle will be suflicient to slacken the flexible connection so that the motor will roduce tension in the driving belt indepen ently of the effect of the treadle spring after the belt has been shifted. The natural condition of operation will be such that the operator will. find it most convenient to hold the treadle completely depressed so as to release the flexible connecas to partially overcome the effect of the weight of the motor in producing belt tens1on. I

i The particular nature of the invention, as

well as other objects and'advantages thereof,

will appear more clearly from a description of certain referred embodiments as lllllS- trated in t e accompanying drawings, in which Figure 1 is an end elevation of a sewing machine having the belt shifter applied to the motor;

Fig. 2 is a rear elevation of the frame of the machine with the apparatus in' place thereon;

Fig. 3 is an enlarged detailed view of a belt shifter;

Fig. 4 is an end elevation of a sewing machine in which the movement of the motor shifts the driving belt and controls the tension of the same;

' t Fig. 5 is a' rear elevation of the apparatus of Fig. 4:; and

Fig. 6 is an enlarged detail view showing the belt shifter of Figs. 4 and 5.

The sewing machine illustrated somewhat diagrammatically in the drawings comprises a table 10 carried upon standards 11 and serving as a support for the frame 12 which comprises a vertical portion and a horizontal portion carrying at its outer end the usual member within which the mechanism for reciprocating the needle is mounted, this mechanism being driven by a shaft carrying a belt pulley 13, and hand Wheel 14. Mounted adjacent the hand wheel is an electric motor 15 which as shown herein is carried upon a bracket like that disclosed in my copending application, Serial No. 343,215, filed December 8, 1 919,'but it will be understood that the motor may be supported adjacent the machine wheel in any other suitable manner, as for instance, by being mounted directly upon the table of the machine, particularlyin case the arm of the machine carries mechanism which might interfere with the application of a bracket.

The supporting bracket shown herein comprises a member 16, having at its inner end upper and lower extensions 17 and 18,

respectively, adapted to fit over the top and] bottom of the horizontal arm of the frame 12. The supporting member is bent outwardly as indicated in Fig. l to clear the machine wheel and bring the motor in proper relation to this wheel. In the supsupporting member and hold it more se-,

curely upon the machine frame to prevent displacement or dislodgement due to the vibration of the motor, or from any other cause. This auxiliary supporting member consists of a strip of metal or other suitable material having a flat upper portion adapted to be seated upon the top'of the machine frame and provided with apertures through any one of which the usual spool spindle 20 may be passed to hold the supporting member more securely in place upon the frame. The dependin portion of the strip is turned upwardly to form a hook within which the main supportin member is seated as shown most clearly in Fig. 2. The outer end of the supportin member -16 is bent at right angles to form an ear 21. Another ear may be formed by cutting a portion of the sup porting member 16 and'bending it at right angles. The ears carry a pin 22 which passes through lugs 23 associated with the motor casing. Placed upon the pin '22 between the motor lugs is a split clamp 24 of any suitable construction which serves to hold the motor in proper position longitudinally of the bracket.

The supporting bracket 16 is so constructed as to bring the pivot pin 22 in proper relation to the driving pulley of the machine to permit the motor to fall away from the machine to maintain tension in the driving belt 25 which passes over the machine pulley 14 and over one or the other of a pair of adjacent loose and fast pulleys 26 and 27, respectively, mounted on the shaft of the motor.

For the purpose of throwing the belt 25 from one pulley to the other, there is provided a lever 28 pivotally mounted upon a bracket 29 attached to the casing of the motor. The lever is provided with an extension 30 having a forked outer end 31 adapted to engage the belt to shift the latter from one pulley to the other when the lever is rocked. The bracket 29 may be provided with stops 32 and 33 to limit the movement of the belt shifter to prevent itv from throw ing the belt off of either of the pulleys. One end of the lever 28 is weighted as at 34, and to the other end of the lever is connected a link 35 which is adjustably connected, as by means of a clamp 36 to a flexible connection 37 which is attached at its other end to a treadle 38 mounted upon a base 39 which may be placed in convenient positionto be reached by the operators foot.

the treadle is a spring 40 whichnormally rFaises the treadle into the positionshown in In the operation of the mechanism described above, the spring 40 normally holds the treadle 38 in elevated position, and by means of the flexible connection 37 and link 35 the lever 28 of the belt shifter is held in position to keep. the belt upon the, loose pulley, so that although the motor be running, no power will be transmitted from it to the machine. When it is desired'to drive the machine, the treadle 38 will be depressed against the effect of'spring 40 to permit the Beneath i lever28 to turn under the influence of its weight 34 and shift the beltfrom the loose pulley 26 to the fast pulley 27, the extension 30 engaging the stop'33 to limit the'movement of the shifter, and prevent it from throwing the belt ofl of the pulley. Power will immediately be transmitted to the machine which will continue in operation 'until the belt is thrown to the loose pulley by re moving the foot from the treadle so that the spring 40 will be free to exert. its force in tilting the lever 28 into position to shift the belt onto the loose pulley 26, the extension 30 at this time engaging the stop 32 to limit its movement. By virtue of the arrangement by which the motor is supported so that its weight produces tension in the driving belt, the motor may swing slightly about the pivot pin 22 as the belt is shifted from one pulley to the other, but it will not be possible for the operator to alter the normal position of the motor, at least by manipulation of the treadle, so that he will be unable.

to decrease the speed of his machine unless he should attempt to do it. by. tilting the motor with one of his hands, but he could I preceding figures, but the cord 37- instead of being connected to a belt shifter is attached to a lug 41 on the side of the motor lymg toward the machine so that the normal action of the spring 40 is to draw the motor towardthe machine to slacken the belt and prevent it from transmitting motionto the wheel of the machine. In order to prevent the motor from being thrown over Its pivot, 1n whlch case it would fall with a weight 48, and between the weight with relatively high flanges 45 to prevent" any danger of the driving-belt 25. 'being thrown off of the .pulleyswhile it is being shifted, or while it is slack.

r The "mechanism for. effecting the shifting, of the belt comprises a lever 46 pivotally mounted upon the bracket 16 and provided with a forked extension 47 to engage the belt. The other end of the lever is provided and the pivot of the lever is a slot 49 whlch receives a pin 50 on the endof a bracket 51 attached to the motor. A stop pin 52 projecting from bracket 16 limits the downward movement of the lever.

The elements of the mechanism are so constructed and related to each other that when the treadle 38 occupies its normal position under the influence of spring 40, the connection 37 will draw the motor into a position such as shown in Fig. 4 in which the shaft of the motor lies on a I line A passing through the pivot pin of the motor. When the motor occupies this position the bracket 51.will through its pin and slot connection with lever 46 elevate the latter into the posit. tion shown in Fig. 5 and. hold the driving belt 25 u n the loose pulley 43 so that no power Wlll be transmitted to the machine,

and since the motor is drawn toward the machine the belt will be relatively slack.

When it is desired to drive the machine the operator de resses the treadle 38 to overcome the e ect of the spring 40 and release the connection 37 to permit the motor to fall away from the machine. This movement of the motor will be accompanied by a corresponding movement of the bracket 51 which will release the lever 46 so that I vunder the influence of the weight 48 the lever will fall upon the stop 52 and shift the belt 25 from the loose pulley 43 to the fast pulle 44. It is intended that the shifting o the belt shall occur during the initial movement of the motor away from the machine asthe treadle is depressed, but on account of the slot 49 the motor may con:

tinue itsmovement away from the machine after the belt has been shifted. Under normal conditions of operation the treadle 38 will be depressed until its outer end rests upon the base 39, inwhich case the motorwillfall into a position in which its weight will roduce such a tension in the belt as I to'drive the machine at the predetermined speed for most .eflicient operation. Preferably the flexible connection 37 should be of is a stop 42 contension motor.

such a length. that when the treadle 36 occupies its completely de ressed osition the connection will become s ack so t at thebelt roduced. by the weight of the motor w 1 not be lessened b the opposin effect of the s ring 40. The motor wi thus be free to rive the machine at the predetermined speed regarded as suitable for most efliclent operation.

*In 'case it is desired to' lessen the speed, thetreadle willbe lifted sufficiently to take up the slack in the flexible connection and.

then pull the latter enough to partially overcome the effect of the weight of themotor upon the tension of the belt. There "will thus be produced between the belt and the pulleys to which it is connected at this time, a certain amount of slip which will result in a decreased speed of operation of the machine without changing the speed of the motor by means of a rheostat'or similar 7 device. During such movements of the motor the pin 50 will move freely in the'slot so that: the belt will not be shifted from the fast pulley. When it is desired to stop the machine the treadle will be released to permit the spring 40 to elevate it into its normal position and through the connection 3'? even if shifted quickly by a sudden, actuation or release of the treadle, or if allowed to lay slack upon the fast pulley.

The inventlon thus provides. a motor drive fora sewing machine which is of simple, construction and eliminates the use of a delicate and expensive instrument such as a rheostat for controlling the speed of the Since the motor is continuously running at high speed the machine startsqfllickly whenever the belt, is shifted onto t e fast pulley and tightened. The arrangements of the invention insure that un- '49 of the lever 46 without lifting the lever,

ere is no danger of the. belt being thrown off of either of the pulleys,-

der normal conditions of operation the sewing machine shallbe driven at maximum speed sothat the efiiciency of the operator is not'lessened. To meet the cases in which it is desired that the operator may exercise some control over the speed of the machine the invention provides an arrangement in conjunction with the belt shifter forro- Y ducing changes in the speed of the mac ine by changes in the position of the motor, and preferably the arrangement is such that these changes require that the operator hold the treadle in an intermediateposition which is not only less comfortable, but renders it more difficultto maintain a constant speed of the machine than when thetreadle lever mounted uponthe motorand provided 7 is in fully depressed position, which is in the nature of a stopposition and may be maintained by the operator with comparatively little effort.

usual condition of the machine will be either one -in which the motor-is entirely out of operative relation to the machine, due to. the driving belt being held upon the loose account of the belt being shifted to the fast pulley, in which case the tension of the belt isinaintained by the weight of the motor independently of the spring. However, it 1 is possible by employing the arrangement shown in Figs. 4, 5 and 6 to produce a third condition in which the motor is held in operative relation to the machine under the balanced effect of its weight and the force exerted by the spring so that changes in speed of the machine maybe obtained.

While certain preferred embodiments of theinvention have been shown and described, it will be understoodthat various changes in the details of construction may bernade without departing from the principle of the invention as defined in the ap pended claims.

Cross reference is hereby made under the provisions of Rule 43, to. copending application, Serial No. 343,216, filedDecember' I claim:

1. In a sewing machine provided with a driving wheel, the combination of aipivot ally mounted motor provided with fast and loose pulleys, a belt associated with the pulleys and the driving wheel ofthe ma-. chine and adapted to be held under tension by the weight of the motor, and means mounted on the motor for shifting the belt from one pulley to-the other.

2. In a sewing machine provided with a driving wheel, the combination of a pivotally mounted motor provided with fast and loose pulleys, a belt associated with the pulleys and the driving wheel of the machine and adapted to be held under tension loose pulleys, a belt associated with thepulleys and the driving wheel of the machine and adapted to be held under tension by the weight of the motor, a weighted In both' ofthe embodi-. ments of the invention illustratedherein the direction.

with a belt engaging member, a spring for by its weight to shift the belt in the opposite 4. In a sewingl machine" provided witha driving wheel, t e combination of apivotally mounted motor provided with fast and loose pulle s, a 'belt. associated with thepulleys an the driving wheel of the 'ma-v chine and adapted to be held under tension by the weight of the motor, a lever mounted belt -engaging member, means for actuating the lever. to shift the belt from the fast pulley to the loose pulley and adapted to be overcome by the operator to release the lever to permit it to shift the belt-from the loose ally mounted motor provided with fast 3 and loose, pulleys, a belt associated with the p ulleysand the driving wheel of the -maso; adjacent to themotor'and provided with a I chineand adapted'to be held under tension by the weight of the motor, a lever mounted adjacent the motor provided at one end with aweight and having a belt engaging member, means-connected to the other end of the lever for swinging the lever to shift the belt. fromone pulley to the other, andjadapted to be overcome by the operator to permit the the opposite direction.

6. In a sewin driving wheel, t e combination of a pivotally mounted motor-providedwith fast and loose pulleys, a belt associated with the pulweight to swingthe lever to shift the belt in and meansjmounted on the motor for shifting the belt from one pulley to the other.

provided with fast andloose pulleys, a belt associated with the pulleys and the driving vwheel ofthe machine, a lever mounted adjacent the motor and provided at one end with. a weight adapted to swing the lever in a direction to shift the belt from the loose pulley tothe fast pulley and means attached to the other end. of the lever for overcoming the effect of the weight to swing the lever in a direction to shift the belt from the loose pulley to the fast pulley, said means being adapted to be overcomeby an operator-to permit the weight to function.

8. In, a sewing machine provided with a driving wheel, the combination of a motor provided with fast and loose pulleys, a belt associated with. the pulleys and the driving wheelof the machine, a bracketattached to themotor: and provided with a pair of stops,

machine provided with a leys and the driving wheel of the machine,

a lever pivotally attached to the bracket and provided with an extension lying between the stops and having a belt engaging fork at its outer end, a weight at one end of the lever for rotating the same to shift the belt from the loose pulley to the fast pulley, a treadle, a connectionbetween the treadle and the other end of the lever'and a spring for swinging the treadle to rotate the lever in a direction to lift the weight and shift the belt from the fast pulley to the loose pulley.

9. In a sewing machine provided Witha driving wheel, the combination of a motor provided with fast and loose pulleys, a belt associated with the pulleys and the driving wheel of the machine, a weighted lever mounted adjacent the motor and provided with a belt shifting member, a member connected at one endtothe lever and a springpressed treadle to which the other end of' the member is connected and adapted when in one extreme position to hold the lever in position to hold the belt upon the loose pulley and when in another extreme position to release the member sufliciently to permit the lever to swing under the influence of its weight to shift the belt onto the fast pulley to drive the machine.

10. In a sewing machine provided with 'a driving wheel, the combination of a pivotally mounted motor provided With fast and loose pulleys, a belt associated with the puileys and the driving wheel of the machine and adapted to be held under tension by the weight of the motor, means for swin ing' the'motor toward the machine to pro uce slackin the belt, and adapted to be overcome by the operator to permit the motor to swing away from the machine to tighten the belt, and means actuated by the motor as it swin s away from the machine to shift the belt rom the loose pulley to the fast pulley.

11. In a sewing machine provided with a driving wheel, the combination of a pivotally mounted motor provided with fast and.

loose pulleys, a belt associated '.with the to move the belt onto the fast pulley.

12. In a sewing machine provided with a-drivling wheel, the combination of a-pivotally mounted motor provided with fast and loose pulleys, a driving belt associated with the pulleys and the driving wheel of the machine and adapted to be held under tension by the weight of the motor, a belt shifter mounted adjacent the motor. means associated with the motor for controlling the movement of the belt shifter, means for swinging the :motor toward the machine to produce slack in the belt and through said controlling means actuate the shifter to move the belt onto the loose pulley, said swinging means being adapted to be overcome by the operator to permit the motor to swing away from the machine to release the shifter to move the belt onto the fast pulley and tighten the beltso that the machine may be driven.

In testimony whereof I aifix my signature.

HYMAN MAIMIN. h 

